Why is the world enamored by the Leader principle (except Switzerland)?

A single person in any capacity of making decisions is subject to advancing his own self-interest, subject to bribery, and subject to threats. Let us call this “corruption.”

I advance the following claim.

If it is possible for a leader to be corrupted, he will be corrupted.

This is just a rephrasing of the old adage that power tends to corrupt.

The ancient world of the Greeks and Romans knew this, and called a single leader a “dictator.” To offset this evil, Sparta had two kings, while the Roman Republic had two consuls — with veto powers over each other.

So why is it that everywhere in the world, we democratically give power to dictators?